Search Results

You are looking at 1 - 10 of 1,242 items for :

  • cluster analysis x
Clear All
Free access

Ruby Valdez-Ojeda, José Luis Hernández-Stefanoni, Margarita Aguilar-Espinosa, Renata Rivera-Madrid, Rodomiro Ortiz and Carlos F. Quiros

of morphological data. A cluster analysis was performed to group the individuals from both studied sites according to similar morphological traits based on different quantitative and qualitative descriptors of the capsule, flower, and seed. To form

Free access

Steven F. Price, Marc L. Schuette and Elizabeth Tassie

Digital imaging and analysis was used to quantify and characterize the light exposure patterns of photosensitive paper tubes placed in representative cluster positions in two grape (Vitis vinifera L.) canopies: a minimally pruned and a vertically trained canopy. Blue pixel values of the captured images had a negative correlation with the log of irradiance from an integrating quantum sensor (r2 = 0.9308). The spectral response of the photosensitive paper was not measured. Histograms of incident light distribution on individual paper tubes were developed using imaging software. Histograms were able to quantify the distribution of incident light on individual tubes and were clearly related to the tube's exposure in the canopy. Average population curves of pixel light distribution of 20 tubes in each canopy were able to differentiate the typical cluster light environment in the two canopies. Tubes in the minimally pruned canopy had a larger proportion of their surface exposed to irradiances > 50 μmol·s-1·m-2 and 65% higher average irradiance than the vertical canopy. Image analysis of photosensitive paper appears to be a workable method to record the distribution ofincident light in plant canopies and may have utility in a range of ecological studies.

Free access

Steven F. Price, Marc L. Schuette and Elizebeth Tassie

Digital imaging and analysis was used to quantify and characterize the light exposure patterns of photo-sensitive paper tubes placed in representative cluster postions in two grape (Vitis `vinifera L.) canopies: a minimally pruned and a vertically trained canopy. Blue pixel values of the captured video images had a strong negative correlation with the log of irradience from an integrating quantum sensor (R2=0.9308). Histograms of incident light distribution on individual paper tubes were developed using imaging software. Histograms were able to quantify the spatial distribution of light on individual tubes and were clearly related to exposure in the canopy. Average population curves of light distribution were able to differentiate the typical cluster light environment in the two canopies. Tubes in the minimally pruned canopy had a larger proportion of their surface exposed to irradiences greater than 50 μmol s-1m-2 and 65% higher average irradience than the vertical canopy. Image analysis of photo-sensitive paper appears to he a workable method to record variation in spatial and temporal light in plant canopies.

Free access

Alireza Talaie* and Rasoul Akrami

The objective of this study was the identification of existing olive trees in eight regions of Kermanshah province and investigation of their fruit, seed, and leaf characteristics in order to be used in the olive production industry of Iran. The germination ability of olive seed in field and nursery were also studied. In this research, 61 genotypes were identified and their characteristics were studied. It was found out that the present genotypes of Kermanshah showed different vegetative and reproductive growth based on the climatic and topographic conditions. This was verified by cluster analysis of the genotypes of different regions, which showed clearly their far and close relations. It was found out that some of the genotypes in the region spite of their appearance differences have same origin and most probably should be considered as the same genotype. The results also showed that favorable seed bed, planting depth and scarification of the seeds have positive effects on their germination while scarification of the seeds without other treatments had no significant effect on the seed germination.

Full access

Joseph Monson and Denise Mainville

respect to farm characteristics, production techniques, marketing strategies, and producer socioeconomic characteristics. Groups of berry producers were characterized using cluster analysis of the survey data. Three types of producers were identified: the

Free access

Xinyi Zhang, Li Liao, Zhiyong Wang, Changjun Bai and Jianxiu Liu

fit between the cluster analysis and the original distance matrix for three data sets (ISSR, SRAP, and ISSR + SRAP). Results Polymorphism analysis. Twenty-five ISSR primers amplified 283 scorable bands, with an average of 11.32 amplified fragments per

Free access

Xiaobo Zhang, Derong Su, Luyi Ma and Yan Zhao

conducted by using module DCENTER and EIGEN of NTSYSpc ( Gower, 1996 ). This multivariate approach was chosen to complement the cluster analysis information; because cluster analysis is more sensitive to closely related individuals, the PCO is more

Full access

Chaowei Song, Qi Wang, Jaime A. Teixeira da Silva and Xiaonan Yu

variables in hierarchical cluster analysis, we classified the fragrance patterns of herbaceous peony cultivars for the first time by combining these results with the identification of the main aromatic compounds and the results of sensory evaluation. This

Free access

Zhiyi Bao, Bo Chen and Hua Zhang

autumn; 2) characterize phenotypic diversity among these accessions using cluster analysis; and 3) select some accessions with good characters to use in the landscape. Materials and Methods Seedlings were collected from Liuyang City, Hunan Province

Open access

Ariana Torres, Petrus Langenhoven and Bridget K. Behe

Windows, v 9.4; SAS Institute Inc., Cary, NC). Last, investigators performed a k-means cluster analysis using the FASTCLUS procedure of SAS software. Cluster analysis has been widely used to define consumer segments based on their preferences and attitudes